This invention relates to hand tools with foldout blades, and, more particularly, to such hand tools with multiple foldout locking blades.
Hand tools with multiple deployable blades have long been known and used in the home, in the workplace, and in sporting applications. A folding pocket knife having two blades is an example. The blades are carried inside a handle for storage, and are selectively opened, one at a time, when required to perform specific functions.
Pocket-knife-like devices, such as those produced by Wenger and Victorinox and commonly called "Swiss Army" knives, use this same principle extended to a plurality of tools carried within the body of the knife on axles located at either end of the knife. Such implements typically incorporate a variety of types of blade-type tools, such as one or more sharpened blades, a screwdriver, an awl, a file, a bottle opener, a magnifying glass, etc. Generally, Swiss Army knives are designed to be sufficiently small and light for carrying in a pocket and are therefore limited as to the strength and robustness of their structure.
In recent years, devices known generically as "combination tools" have been developed and widely marketed. A combination tool is built around a jaw mechanism such as a full-size pliers head. The pliers head has handles fixed thereto. To make the combination tool compact yet capable of use in situations requiring the application of large forces, the handles are made deployable. To make the combination tool more useful, a number of blade tools, generally of the type found in the Swiss Army knife, are received in a folding manner within the handles themselves.
One useful feature of some conventional folding knives is the ability to positively lock the blade in the open position to prevent an unintentional closure during service that could cut the hand of the user. Lockbacks, sidelocks, axle locks, and other types of locks are known in the art. Another useful feature is the biasing of the blade toward its closed position from angular orientations close to the closed position. Such a biasing acts as a detent to prevent the blade from unintentionally folding open when carried or when another blade is already open and in use. The blade may also be biased toward its open position from angular orientations close to the open position. In either case, the biasing effect gives a secure feel to the closing and opening of the blades. Cam, backspring, ball detent, and other types of biasing structures are known in the art.
Positive locks used in conjunction with biasing structures are desirable features of knives, but they have not been successfully utilized in knives having multiple blades rotating in the same direction on a common axle. (When the term "blade" or "blade tool" is used herein in reference to deployable tools received into the handle of the combination tool, knife, or other type of tool, it refers to any relatively thin tool that is folded into the handle, regardless of the utilization of the tool. Such a "blade" therefore includes, but is not limited to, a sharpened knife blade, a serrated blade, a screwdriver, an awl, a bottle opener, a can opener, a saw, a file, etc.) Existing approaches have internal structures that require too much space when adapted for use on several side-by-side blades, or the locking release controls take up too much space or are inconvenient. For example, a typical combination tool has four or more blades folding from a common axle in each handle, where the width of the handle--the required envelope size within which the entire structure must fit--is on the order of about 1 inch or less. The sides of the handle, the blades, and any locking and biasing mechanism must fit within that width, and the externally accessible lock releasing structure must also fit on the outside of the handle within that width. If the width of the handle of the hand tool is increased significantly above about 1 inch, the combination tool will no longer be comfortable in the hand. There have been some attempts to provide a positive lock for the blades of a combination tool, but they have been highly inconvenient to use in practice.
There is a need for an approach to locking and biasing multiple, side-by-side blades of combination tools, knives, and other types of hand tools where the blades pivot on a common axis. The present invention fulfills this need, and further provides related advantages.